enc_read.c

/* crypto/des/enc_read.c *//* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. * * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to. The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code. The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). * * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * "This product includes cryptographic software written by * Eric Young (eay@cryptsoft.com)" * The word 'cryptographic' can be left out if the rouines from the library * being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from * the apps directory (application code) you must include an acknowledgement: * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" * * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed. i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */#include <stdio.h>#include <errno.h>#include "cryptlib.h"#include "des_locl.h"/* This has some uglies in it but it works - even over sockets. *//*extern int errno;*/
OPENSSL_IMPLEMENT_GLOBAL(int,DES_rw_mode)=DES_PCBC_MODE;
/* * WARNINGS: * * - The data format used by DES_enc_write() and DES_enc_read() * has a cryptographic weakness: When asked to write more * than MAXWRITE bytes, DES_enc_write will split the data * into several chunks that are all encrypted * using the same IV. So don't use these functions unless you * are sure you know what you do (in which case you might * not want to use them anyway). * * - This code cannot handle non-blocking sockets. * * - This function uses an internal state and thus cannot be * used on multiple files. */int DES_enc_read(int fd, void *buf, int len, DES_key_schedule *sched,
DES_cblock *iv)
{
/* data to be unencrypted */int net_num=0;
staticunsignedchar *net=NULL;
/* extra unencrypted data * for when a block of 100 comes in but is des_read one byte at * a time. */staticunsignedchar *unnet=NULL;
staticint unnet_start=0;
staticint unnet_left=0;
staticunsignedchar *tmpbuf=NULL;
int i;
long num=0,rnum;
unsignedchar *p;
if (tmpbuf == NULL)
{
tmpbuf=OPENSSL_malloc(BSIZE);
if (tmpbuf == NULL) return(-1);
}
if (net == NULL)
{
net=OPENSSL_malloc(BSIZE);
if (net == NULL) return(-1);
}
if (unnet == NULL)
{
unnet=OPENSSL_malloc(BSIZE);
if (unnet == NULL) return(-1);
}
/* left over data from last decrypt */if (unnet_left != 0)
{
if (unnet_left < len)
{
/* we still still need more data but will return * with the number of bytes we have - should always * check the return value */
memcpy(buf,&(unnet[unnet_start]),
unnet_left);
/* eay 26/08/92 I had the next 2 lines * reversed :-( */
i=unnet_left;
unnet_start=unnet_left=0;
}
else
{
memcpy(buf,&(unnet[unnet_start]),len);
unnet_start+=len;
unnet_left-=len;
i=len;
}
return(i);
}
/* We need to get more data. */if (len > MAXWRITE) len=MAXWRITE;
/* first - get the length */while (net_num < HDRSIZE)
{
#ifndef _WIN32 i=read(fd,(void *)&(net[net_num]),HDRSIZE-net_num);
#else i=_read(fd,(void *)&(net[net_num]),HDRSIZE-net_num);
#endif#ifdef EINTRif ((i == -1) && (errno == EINTR)) continue;
#endifif (i <= 0) return(0);
net_num+=i;
}
/* we now have at net_num bytes in net */
p=net;
/* num=0; */
n2l(p,num);
/* num should be rounded up to the next group of eight * we make sure that we have read a multiple of 8 bytes from the net. */if ((num > MAXWRITE) || (num < 0)) /* error */return(-1);
rnum=(num < 8)?8:((num+7)/8*8);
net_num=0;
while (net_num < rnum)
{
i=read(fd,(void *)&(net[net_num]),rnum-net_num);
#ifdef EINTRif ((i == -1) && (errno == EINTR)) continue;
#endifif (i <= 0) return(0);
net_num+=i;
}
/* Check if there will be data left over. */if (len < num)
{
if (DES_rw_mode & DES_PCBC_MODE)
DES_pcbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);
else
DES_cbc_encrypt(net,unnet,num,sched,iv,DES_DECRYPT);
memcpy(buf,unnet,len);
unnet_start=len;
unnet_left=num-len;
/* The following line is done because we return num * as the number of bytes read. */
num=len;
}
else
{
/* >output is a multiple of 8 byes, if len < rnum * >we must be careful. The user must be aware that this * >routine will write more bytes than he asked for. * >The length of the buffer must be correct. * FIXED - Should be ok now 18-9-90 - eay */if (len < rnum)
{
if (DES_rw_mode & DES_PCBC_MODE)
DES_pcbc_encrypt(net,tmpbuf,num,sched,iv,
DES_DECRYPT);
else
DES_cbc_encrypt(net,tmpbuf,num,sched,iv,
DES_DECRYPT);
/* eay 26/08/92 fix a bug that returned more * bytes than you asked for (returned len bytes :-( */
memcpy(buf,tmpbuf,num);
}
else
{
if (DES_rw_mode & DES_PCBC_MODE)
DES_pcbc_encrypt(net,buf,num,sched,iv,
DES_DECRYPT);
else
DES_cbc_encrypt(net,buf,num,sched,iv,
DES_DECRYPT);
}
}
return num;
}